Vinylidene chloride copolymer



Patented Apr. 8, 1941 "UNITED. STATES PATENT OFFICE VINYLIDENE CKIDBIDE COPOLYMEB Alden W. Hanson and William C. Goggin, Midland, Mich assignors to The Dow Chemical Company, Midland, Mich, a corporation of Michigan 1 No Drawing. Application June z, 1939, Serial No. 17,055

5 Claims. (CL 260-84) This invention relates to copolymers of vlnylidene chloride and vinyl cyanide or alpha-lower alkyl derivatives of vinyl cyanide. Such compounds have the general formula to about 90 C. under the vapor pressure of the reactants. A convenient temperature range is from 30' to 60 C. The polymerization rate can be accelerated by carying out the reaction in the presence ofcatalysts such as benzoyl peroxide, hydrogen peroxide or uranium salts as catalysts, ON or by subjecting the copolymerizing mixture to the effects of light, or to the combined effects oi where R is hydrogen or a lower alkyl group conlight. catalyst and heat. taining from 1 to 5 carbon atoms inclusive. The polymer of vlnylidene chloride alone has Copolymers of vlnylidene chloride have been, ,a softening point near 210 (3., and that oi vinyl made heretofore with a wide range of copolycyanide softens near 215' C., while copolymers merizing compounds, and exhibit a wide range of the two soi'ten at temperatures low enough so of physical properties. In many cases the cothat they may be molded conveniently at 160- polymer has a lower "softening point than has 190' C. For example, the copolymer oi 95 per polymeric vlnylidene chloride alone, and hence cent vinyl cyanide and 5 per cent vinylidene is more easilydeiormed plastically to give shaped chloride softens at about 188 C., and that of 5 articles. Such softening point lowering is generally accompanied, in vlnylidene chloride codene chloride soitensat about 190 C. polymers, by other soiteness characteristics, and quite commonly by lowering of tensile strength, toughness, and dielectric strength to too great an extent. It is desired to produce a tough plastic having good tensile strength and good dielectric strength. It is also desirable to pro duce a plastic having high strength and hardness values, coupled with toughness. I

It is accordingly an object of the present in- '75 parts by weight 01 monomeric vlnylidene vention to provide a polymeric plastic which chloride, boiling between 31-32 C. and 25 parts has to a Practical degree at least a p rality of by weight of monomeric vinyl cyanide, boiling the properties of toughness, hardness, dielectric between 7647 C., were mixed. To the mixture strength, and ten i e s r n h t is another of monomers was added 0.5 per cent by weight object to provide a vlnylidene chloride copolymer of benzoyl peroxide t t, The mixture which has a lower so n poi t h n vinyli- 35 was sealed in a pressure vessel and subjected to dene chloride alone and which has at least a a temperatureoi about C. for 11 days. The plurality of the properties of toughness. hardnes di l ct i strength d nsil t ens nearly transparent glassy mass after it had been with values higher th n th r lly en mdried to remove traces of remaining monomers. tered for these combinations of propertiesyin Portions of the polymeric product were molded most polymeri Plastics It is E further Object at 170C. to form test specimens. The product t pr v new and useful copolymers Ofv vinylihad a Shore hardness of 87, a tensile strength dene chloride and vinyl cyanide or alpha-alkyl derivatives of vinyl cyanide. cross section and an impact strength of 3.4 inch It has now been found that the foregoing ob- 45 pounds, iects may be attained, and useful copolymers produced having an unusual combination of toughness, hardness, dielectric and tensile values, by polymerizing together vlnylidene chlo- The.copolymers intermediate between those defined above have still lower softening points, and can be molded at temperatures generally below 180! C.

The, following examples illustrate the practice of the invention;

Example 1 Example 2 ample 1, a series of copolymers of vlnylidene ride and vinyl cyanide or alpha-alkyl derivatives chloride and vinyl cyanide were prepared, analysis thereof, to produce copolymers having from about 5 to'about 95 per cent of the vinyl cyanide citm'llt o'llnd copo y with r p ndingly versely from 95 to 5 per cent of vinyl cyanide. from 95 to 5 per cent of vlnylidene chloride. I Various properties of each sample were tested 24 The polyme i ti y be effected at perahours after the copolymer had been preformed showing the finished copolymers to contain from 5 to per cent vlnylidene chloride and contures ranging from about room temperature up per cent vinyl cyanide and 95 per cent vinyli polymeric product obtained was a light yellow,

, of 10,500 pounds per square inch of original In a manner similar to that set forth in Ex into test samples by a simple molding operation. Each 01' the values reported is an average of several determinations on the same or companion samples. Impact strength, expressed in inch pounds, is given as a measure of toughness of the product. Shore hardness, which is a measure of a combination of hardness, resilience and elasticity, and standard superficial Rockwell hardness, using a 0.5 inch diameter steel ball, are both reported. Tensile strength is given in terms of pounds load per square inch of original crosssectional area required to rupture a test specimen. Dielectric constant is reported as determined in the usual manner.

Vinyl Shore Rockwell Sample Im- Dielectric Tensile h N n. g zggi pact constant strength a s. l s. 95 4, 200 is m 2. 7 3. 24 3. 600 51 l5 2. 5 2. (ll 4, 700 71 5G 3. 2 3. 2 6. 800 X3 2.5 a, 4 3. 17 10,500 a: 94 2. 4 3. l6 9, an RX 95 2. ll 9, 600 83 88 so 2. 4 3. 68 10.100 94 75 96 95 1. 7 95 Example 3 Tests similar to those reported in Example 2 were carried out on several samples of vinylidene chloride-vinyl cyanide copolymers one week after molding the test specimens.

It is observed from the data set forth in the examples that the copolymers of vinylidene chloride and vinyl cyanide have a remarkable combination of properties, each one possessing a high value for at least two of the properties of toughness, hardness, dielectric strength and tensile strength, especially if considered in comparison with other polymeric plastics, including many of the copolymers of vinylidene chloride with compounds other than vinyl cyanide. These properties, together with that of lowered softening point makes these copolymers especially advantageous in preparing molded and extruded shaped articles.

The invention has been illustrated with respect to copolymers of vinylidene chloride and vinyl cyanide. Similarly advantageous properties may be obtained in the copolymers of vinylidene chloride and the alpha-lower alkyl derivatives of vinyl cyanide, examples of which are alphamethyi vinyl cyanide, alpha-ethyl vinyl cyanide, alphabutyl vinyl cyanide and alpha-amyl vinyl cyanide.

The copolymers of the invention may be modified as to properties by the inclusion of plasticizers, pigments, dyes or fillers, before or after polymerization, depending on the efiect these materials have on the polymerization of the mixed monomers and on the effect desired.

We claim:

1. A copolymer of from 5 to per cent of vinylidene chloride and correspondingly from 95 to 5 per cent of a compound having the general formula ll.'(':C

ox wherein R is selected from the class consisting of hydrogen and the lower alkyl radicals containing from 1 to 5 carbon atoms inclusive.

2. A. copolymer of from 5 to 95 per cent of vinylidene chloride and correspondingly from 95 to 5 per cent of vinyl cyanide.

3. A copolymer of from 5 to 95 per cent of vinylidene chloride and correspondingly from 95 to 5 per cent of an alpha-lower alkyl derivative of vinyl cyanide, wherein the lower alkyl group contains from 1 to 5 carbon atoms inclusive.

4. A copolymer of vinylidene chloride and a compound having the general formula nic=c cs: wherein R is selected'from the class consisting of hydrogen and the lower alkyl radicals containing from 1 to 5 carbon atoms inclusive.

5. A copolymer of vinylidene chloride and vinyl cyanide.

ALDEN W. HANSON. WILLIAM C. GOGGIN. 

